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Abstract:

Fiber optic interface devices (20, 320) for electronic devices (300) are
disclosed. A plug-type fiber optic interface (20) has an axially moveable
multi-fiber ferrule (100) that supports optical fibers (52) or a
combination of optical fibers and gradient-index lenses (600). A
resilient member (150) serves to provide the ferrule with forward-bias
and rear-bias positions relative to a recessed front end (22) of a
housing (21). A fiber optic interface assembly (570) that includes mated
plug and receptacle fiber optic interface devices (20, 320) is also
disclosed.

Claims:

1. A fiber optic interface device for connecting at least one optical
fiber of an optical fiber cable, comprising: a housing having a central
axis, a front end, and an interior having a ferrule guide member attached
to the housing and disposed therein; a ferrule having a central axis,
front and rear ends, and configured to support the at least one optical
fiber having an optical fiber end substantially at the ferrule front end,
the ferrule being moveably supported by the ferrule guide member with the
ferrule axis being aligned with the housing central axis; and a resilient
member disposed within the housing interior and operatively arranged
therein to forward-bias the ferrule toward the housing front end.

2. The fiber optic interface device according to claim 1, further
comprising the ferrule guide member comprising an interior wall with the
housing interior, and an aperture in the interior wall configured to
loosely contain the ferrule to move along the ferrule central axis.

3. The fiber optic interface device according to claim 1, further
comprising first and second guide pins that extend from the ferrule front
end on respective sides of and residing in a common plane with the
ferrule central axis.

4. The fiber optic interface device according to claim 1, further
comprising first and second electrical contacts disposed on opposing
sides of the plug housing, with the first and second electrical contacts
having respective first and second rear portions that extend into the
housing interior.

5. The fiber optic interface device according to claim 1, further
comprising the housing including a recess at the housing front end
configured to allow access to clean the ferrule front end.

6. The fiber optic interface device according to claim 5, further
comprising the housing recess defining first and second prongs on
opposite sides of the recess that serve as alignment features for
connecting the fiber optic interface device to a receptacle.

7. The fiber optic interface device according to claim 1, further
comprising the resilient member comprising a spring.

8. The fiber optic interface device according to claim 7, wherein the
spring has an interior, and wherein the at least one optical fiber
travels from the fiber optic cable through the housing rear and through
the spring interior to the ferrule.

9. The fiber optic interface device according to claim 1, further
comprising the at least one optical fiber having an optical fiber end,
wherein the ferrule includes an angled portion adjacent the ferrule front
surface, the angled portion configured to facilitate laser processing of
the at least one optical fiber supported in the ferrule bores to form the
optical fiber end.

10. An optical fiber cable assembly, comprising: the optical fiber
according to claim 1; and the optical fiber cable operably connected to
the interface device housing rear end, with the at least one optical
fiber passing through the housing rear end and supported in the ferrule.

11. An optical fiber cable assembly, comprising: the optical fiber
according to claim 4; and the optical fiber cable operably connected to
the interface device housing rear end, the optical fiber cable
additionally carrying first and second electrical wires, with the at
least one optical fiber passing through the housing rear end and
supported in the ferrule, and the first and second electrical wires
passing through the housing rear end and electrically connected to the
respective first and second rear portions of the electrical contacts.

12. A fiber optic interface assembly, comprising the fiber optic
interface device according to claim 1; and a receptacle matingly engaged
with the fiber optic interface device, the receptacle acting to place the
fiber optic interface device in a rear-biased position wherein the
ferrule axially moves a distance D in the range from 7 mm to 9 mm.

13. A fiber optic interface device for connecting transmit and receive
optical fibers having respective ends, comprising: a housing having a
central axis, a front end, an exterior surface and an interior having a
ferrule guide member disposed therein; a ferrule having a central axis,
front and rear ends and configured to support the transmit and receive
optical fibers and respective transmit and receive gradient-index (GRIN)
lens elements having front and rear surfaces, with the transmit and
receive optical fiber ends adjacent respective transmit and receive GRIN
lens rear surfaces, with the transmit and receive GRIN lens front
surfaces being at or adjacent the ferrule front end, the ferrule being
moveably supported by the ferrule guide member with the ferrule axis
being aligned with the housing central axis; and a resilient member
disposed within the housing interior and configured to forward-bias the
ferrule toward the housing front end when the fiber optic interface
device is unmated.

14. The fiber optic interface device of claim 13 for connecting first and
second electrical wires of an optical fiber cable, the device further
comprising: first and second electrical contacts disposed on the housing
exterior surface, the first and second electrical contacts having
respective rear portions that reside within the housing interior, said
rear portions being respectively electrically contacted to the first and
second electrical wires.

15. The fiber optic interface device according to claim 13, further
comprising the housing front end having a recess that defines a recessed
front end and first and second prongs on opposite sides of the recess.

16. A fiber optic interface assembly comprising: the fiber optic
interface device according to claim 13; a receptacle being matingly
engaged with the fiber optic interface device such that the ferrule is
axially moved from the forward-bias position to a rear-bias position.

17. The fiber optic interface assembly according to claim 16, further
comprising a distance D between the forward-bias position and the
rear-bias position, wherein the distance D is in the range from 0.5 mm to
10 mm.

18. The fiber optic interface assembly according to claim 16, further
comprising the receptacle having recess features configured to engage the
first and second prongs when the receptacle matingly engages the plug.

19. The fiber optic interface assembly according to claim 16, further
comprising guide pins on the front end of the ferrule, and corresponding
guide-pin holes sized to receive the guide pins when the receptacle
matingly engages the plug.

20. The fiber optic interface assembly according to claim 16, wherein the
receptacle includes transmit and receive GRIN lenses that are operably
aligned with the transmit and receive GRIN lenses of the fiber optic
interface device.

Description:

[0002] The present disclosure relates generally to fiber optic interface
devices, and in particular relates to multi-fiber fiber optic interface
devices for use with electronic devices.

BACKGROUND

[0003] Optical fiber is increasingly being used for a variety of
applications, including but not limited to broadband voice, video, and
data transmission. As consumer devices are steadily using more bandwidth,
interface devices for these devices will likely move away from electrical
connections and toward using optical connections for increased bandwidth.
Generally speaking, conventional fiber optic interface devices used for
telecommunication networks and the like are not suitable for consumer
electronic devices.

[0004] For instance, conventional fiber optic interface devices are
relatively large compared with the consumer electronic devices and their
interfaces. Additionally, conventional fiber optic interface devices are
deployed with great care into relatively clean environments and/or
cleaned by the craft before connecting to the device interface. Further,
even though fiber optic interface devices are reconfigurable (i.e.,
suitable for mating/unmating), they are not intended for a relatively
large number of mating cycles. Instead, conventional fiber optic
interface devices are high-precision interface devices designed for
reducing insertion loss between mating interface devices in the optical
network.

[0005] On the other hand, the consumer electronic devices are expected to
have a relatively large number of mating/unmating cycles during ordinary
operation. The consumer electronic devices will be operated in a
multitude of environments where dirt, dust, and other debris is
encountered on a regular basis. Further, consumer electronic devices
typically have size and space constraints for making connections.
Consequently, there is an unresolved need for fiber optic interface
devices suitable for consumer electronic devices.

SUMMARY

[0006] An aspect of the disclosure is a fiber optic interface device for
connecting at least one optical fiber of an optical fiber cable. The
fiber optic interface device includes a housing having a central axis, a
front end, and an interior having a ferrule guide member disposed therein
and attached to the housing. The fiber optic interface device also
includes a ferrule having a central axis, and front and rear ends. The
ferrule is configured to support the at least one optical fiber having an
optical fiber end substantially at the ferrule front end. The ferrule is
moveably supported by the ferrule guide member, with the ferrule axis
being aligned with (e.g., coaxial with) the housing central axis. A
resilient member is disposed within the housing interior and is
operatively arranged therein to forward-bias the ferrule toward the
housing front end when the fiber optic interface device is not mated
(i.e., is not interfaced) with another fiber optic interface device.

[0007] Another aspect of the disclosure is a fiber optic interface
assembly that includes the fiber optic interface device as described
immediately above, and a receptacle matingly engaged with the fiber optic
interface device. The receptacle acts to place the fiber optic interface
device in a rear-biased position wherein the ferrule axially moves
relative to a recessed front end of the housing.

[0008] Another aspect of the disclosure is a fiber optic interface device
for connecting transmit and receive optical fibers having respective
ends. The device includes a housing having a central axis, a front end,
an exterior surface and an interior having a ferrule guide member
disposed therein and attached to the housing (e.g., fixed thereto). The
device also includes a ferrule having a central axis, and front and rear
ends. The ferrule is configured to support the transmit and receive
optical fibers and respective transmit and receive gradient-index (GRIN)
lens elements having front and rear surfaces. The transmit and receive
optical fiber ends are arranged adjacent respective transmit and receive
GRIN lens rear surfaces while the transmit and receive GRIN lens front
surfaces are arranged at or adjacent the ferrule front end. The ferrule
is moveably supported by the ferrule guide member so that the ferrule can
move axially, with the ferrule axis being aligned with (e.g., coaxial
with) the housing central axis. The device also includes a resilient
member disposed within the housing interior and configured to
forward-bias the ferrule toward the housing front end when the fiber
optic interface device is unmated.

[0009] Another aspect of the disclosure is a fiber optic interface
assembly that includes the fiber optic interface device as described
immediately above, and a receptacle matingly engaged with the fiber optic
interface device. The receptacle acts to place the fiber optic interface
device in a rear-biased position wherein the ferrule axially moves
relative to a recessed front end of the housing.

[0010] It is to be understood that both the foregoing general description
and the following detailed description present embodiments of the
disclosure, and are intended to provide an overview or framework for
understanding the nature and character of the disclosure as it is
claimed. The accompanying drawings are included to provide a further
understanding of the disclosure, and are incorporated into and constitute
part of this specification. The drawings illustrate various exemplary
embodiments of the disclosure, and together with the description serve to
explain the principles and operations of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 and FIG. 2 are front elevated views of an example fiber
optic cable assembly that employs an example fiber optic interface device
in the form of a plug;

[0012]FIG. 3 and FIG. 4 are front and rear elevated cut-away views that
illustrate details of the interior configuration of the plug of FIG. 1
and FIG. 2, with FIG. 4 illustrating laser processing of the optical
fibers using a laser beam;

[0013] FIG. 5 is similar to FIG. 4, but shows the plug ferrule in the
rear-biased position due to an urging force on the plug ferrule in the
axial direction and toward the rear end of the plug housing;

[0014] FIG. 6 is a top-down view of an example electronic device and the
fiber optic cable assembly next to the electronic device;

[0015]FIG. 7A is a close-up, top-down cut-away view of the plug adjacent
the receptacle of the electronic device just prior to engaging the plug
and receptacle;

[0016]FIG. 7B is similar to FIG. 7A, but shows the plug matingly engaged
with the receptacle of the electronic device;

[0017] FIG. 8A is a front-elevated view similar to FIG. 2, and FIG. 8B is
a partial cut-away view that illustrates an example embodiment of a fiber
optic cable assembly having a plug that includes gradient-index (GRIN)
lenses;

[0018] FIG. 9 is similar to FIG. 7B and illustrates an example embodiment
of fiber optic interface assembly where the plug and receptacle include
GRIN lenses; and

[0019] FIG. 10 is a close-up view of the interface between the plug and
receptacle showing the interfaced GRIN lenses of the plug and receptacle.

DETAILED DESCRIPTION

[0020] Reference is now made in detail to the present preferred
embodiments of the disclosure, examples of which are illustrated in the
accompanying drawings. Whenever possible, like or similar reference
numerals are used throughout the drawings to refer to like or similar
parts. Various modifications and alterations may be made to the following
examples within the scope of the present disclosure, and aspects of the
different examples may be mixed in different ways to achieve yet further
examples. Accordingly, the true scope of the disclosure is to be
understood from the entirety of the present disclosure, in view of but
not limited to the embodiments described herein.

[0021] In some of the Figures, Cartesian coordinates are shown for
reference. Also, the terms "plug" and "receptacle" are used for the sake
of distinguishing different parts of a fiber optic interface device
assembly that includes two fiber optic interface devices having
complementary geometries. Further, in some of the examples discussed
below, the receptacle is part of an electronic device, and a plug is used
to plug into the receptacle of the electronic device.

[0022] In the discussion below, the term "electronic device" means a
device that has either electronic or optical and electronic components
and functionality, including a receptacle and associated hardware
configured to receive, transmit or both transmit and receive optical
signals and also communicate electrical power.

[0023] FIG. 1 and FIG. 2 are front elevated views of an example fiber
optic cable assembly 10 that includes a fiber optic interface device 20
operably connected to a fiber optic cable 50. In an example, fiber optic
cable 50 carries at least one optical fiber 52, e.g., two optical fibers,
with one being a transmit fiber and one being a receive fiber for
respectively carrying transmit and receive optical signals. Also in an
example embodiment, fiber optical cable 50 carries at least one
electrical wire 54, e.g., two electrical wires ("black and red") that can
carry electrical power. In the example, where fiber optic cable 50
carries both at least one optical fiber 52 and at least one electrical
wire 54, fiber optic interface device 20 can be thought of as a hybrid
electrical-optical (O-E) interface device. FIG. 3 and FIG. 4 are front
and rear elevated cut-away views that illustrate details of the interior
configuration of fiber optic interface device 20.

[0024] As fiber optic interface device 20 is configured to plug into a
complementary fiber optic interface device, it is referred to hereinafter
as plug 20, and the complementary fiber optic interface device introduced
and discussed below is referred to as receptacle 320.

[0025] With reference to FIG. 1 through FIG. 4, plug 20 includes a housing
21 with a central axis A0, a front end 22, a rear end 24 and sides 26
that constitute part of housing exterior surface 27. Rear end 24 includes
an opening 25. A strain-relief member 30 is arranged at rear end 24 of
housing 21 at opening 25 and serves to reduce the amount of strain on
fiber optic cable 50 where the fiber optic cable connects to the housing.
Plug 20 includes a central axis Al that is co-axial with housing central
axis A0.

[0026] Front end 22 of plug housing 21 includes a recess 36 that defines
housing side extensions or prongs 38 that serve to provide alignment with
a complementary receptacle 320 (introduced and discussed below in
connection with FIG. 6 and FIGS. 7A and 7B), to which plug 20 is
configured to matingly engage. Recess 36 thus defines a recessed front
end 22R of housing 21 within recess 36.

[0027] Housing 21 defines an interior 40 that includes a front section 42
open at housing front end 22 and a rear section 44 (see FIGS. 3 and 4).
Front and rear interior sections 42 and 44 are generally defined by an
internal wall 60 having front and rear surface 62 and 64, and a central
aperture 68 open to the front and rear interior sections. Rear interior
section 44 includes interior sidewalls 45 and a floor 47. Rear interior
section 44 also includes a retention feature 70 disposed between interior
wall 60 and housing rear end 24. Retention feature 70 is connected to
floor 47 of rear interior section 44 and includes a central aperture 72
sized to pass optical fibers 52 that pass into rear interior section 44
of housing 21 through the housing rear-end opening 25.

[0028] Plug 20 also includes a ferrule 100 arranged in housing interior
40. In an example, ferrule 100 has an MT configuration. Ferrule 100
includes a front section 101 having a front end 102, and a rear section
103 having a rear end 104. Ferrule 100 also includes a top 105. Ferrule
100 is arranged in housing interior 40 and within central aperture 68 of
internal wall 60 so that ferrule front section 101 resides within front
interior section 42 and ferrule rear section 103 resides within rear
interior section 44. Ferrule 100 has a central axis AF that is aligned
with plug axis A1 when the plug ferrule is arranged in housing interior
40; for example, the alignment can be essentially coaxial alignment, or
it can be slightly offset alignment.

[0029] The ferrule front and rear sections 101 and 103 are defined by a
step 110, with the rear section being wider than the front section.
Ferrule 100 is loosely held within wall aperture 68 so that it can move
axially within plug housing 21. Ferrule step 110 engages the rear surface
64 of internal wall 60 to limit the forward movement of the ferrule 100.
In this sense, internal wall 60 serves as an example of a ferrule guide
member configured to allow ferrule 100 to move axially within housing 21.
Other configurations for a ferrule guide member beyond the example of an
internal wall 60 and aperture 68 can also be employed; for example, the
wall can be attached to plug 20 by being monolithically formed to it, or
wall 60 can be attached by sliding the wall into grooves, slots, latches,
recesses, snap fit structure, or other suitable attachment attributes.
Thus, in an example, a ferrule guide member is disposed within housing
interior 40 and is attached (e.g., fixedly attached) to the housing.

[0030] Plug 20 further includes a resilient member 150 having a front end
152 and a rear end 154. In an example, resilient member 150 is
operatively arranged within housing interior rear section 44 with the
resilient member front end 152 at ferrule rear end 104 and the resilient
member rear end 154 at retention feature 70. Resilient member 150 has a
spring force that serves to urge ferrule 100 to a forward-bias position
when plug 20 is not engaged with a receptacle or is not otherwise
intentionally being urged rearward. The forward-bias position is defined
by the aforementioned ferrule step 110 contacting internal wall rear
surface 64, and places ferrule front end 102 substantially at recessed
front end 22R of plug housing 21.

[0031] Resilient member 150 is also configured to compress to allow for
ferrule 100 to move axially rearward within plug housing 21 when the plug
engages a receptacle or is otherwise urged rearward in the housing. In an
example embodiment, resilient member 150 is a spring with an interior
156, and optical fibers 52 travel through the spring interior to ferrule
100. In an alternate example, retention feature 70 is not employed and
one end of resilient member 150 resides against housing rear end 24
within rear interior section 44.

[0032] Ferrule 100 further includes waveguide bores 160 that extend from
ferrule rear end 104 to ferrule front end 102 where the bores terminate
at bore ends 162. In one example, bores 160 are sized to support optical
waveguides, e.g., optical fibers 52. In an example, ferrule 100 includes
two waveguide bores 160 configured to respectively accommodate two
optical fibers 52, which can be transmit and receive optical fibers.
Optical fibers 52 have optical fiber ends 52E that in one example
terminate substantially at waveguide bore ends 162, i.e., directly at the
waveguide bore ends, or slightly extending from the waveguide bore ends,
or slightly recessed in the waveguide bore ends. Optical fibers 52 are
provided with some slack within rear interior section 44 of housing
interior 40 to accommodate the axial movement of ferrule 100.

[0033] Ferrule 100 also includes an angled portion 170 adjacent ferrule
front end 102 and ferrule top surface 105. Angled portion 170 facilitates
laser processing of optical fibers 52 using a laser beam LB to form
optical fiber ends 52E at or near bore ends 162, as schematically
illustrated in FIG. 4.

[0034] In an example, ferrule 100 additionally includes two guide-pin
bores 180 on respective sides of waveguide bores 160 and that lie in a
common plane with ferrule central axis AF. Guide-pin bores 180
accommodate respective guide pins 190 that have respective front ends 192
and rear ends 194. In an example, a guide-pin retention member 196 is
arranged over ferrule rear section 103 and is fixed to guide pins 190 at
or near guide-pin rear ends 194. Guide-pin retention member 196 serves to
secure guide pins 190 to ferrule 100. In an example embodiment, guide
pins 190 are metallic and serve as conducting members by being
electrically connected at guide-pin rear ends 194 to electrical wire ends
54E.

[0035] In an alternate example embodiment, guide pins 190 are formed
integral with ferrule 100.

[0037] FIG. 5 is similar to FIG. 4, but shows ferrule 100 in a rear-biased
position when subjected to an urging force illustrated by arrow 220. Note
that ferrule front end 102 has moved a distance D from its original
forward-biased position to its rear-biased position. In example
embodiments, distance D is in the range from 0.5 mm to 10 mm, more
preferably in the range from 2 mm to 8 mm and even more preferably in the
range from 5 mm to 7 mm. The forward-bias position is advantageous
because it presents ferrule front end 102 substantially at recessed front
end 22R of housing 21, and this allows for easy access to the ferrule
front surface for cleaning the ferrule. This is important in applications
where plug 20 is used to connect to commercial electronic devices, such
as electronic device 300 introduced and discussed below, because
contamination due to debris, liquids, etc., is anticipated to be a
significant issue in establishing a proper electrical and optical
connection.

[0038] FIG. 6 is a top-down view of an example electronic device 300 and
fiber optic cable assembly 10 next to the electronic device. Electronic
device 300 has a housing 310 with a side 312. Electronic device housing
310 supports the aforementioned receptacle 320 at housing side 312.
Receptacle 320 is a fiber optic interface device having a complementary
geometry to plug 20 and is thus configured to matingly engage with plug
20.

[0039]FIG. 7A is a close-up view of plug 20 shown adjacent receptacle 320
prior to connecting fiber optic cable assembly 10 to electronic device
300. Note that ferrule 100 of plug 20 is in its forward-biased position
in plug housing 21, with ferrule front end 102 substantially at recessed
front end 22R of plug housing 21.

[0040] Receptacle 320 has a central axis A2 and generally has a
complementary geometry to plug 20. In an example, receptacle 320 includes
recess features 338 complementary to prongs 38 so that the prongs and
recess features can engage and serve as an alignment guide when mating
plug 20 to receptacle 320.

[0041] Receptacle 320 has first and second outer walls 340 that partially
define recess features 338. Receptacle 320 further includes first and
second receptacle electrical contacts 350 respectively disposed on the
first and second outer walls 340. These first and second receptacle
electrical contacts 350 come into contact with plug electrical contacts
200 of plug 20 when plug 20 is matingly engaged with receptacle 320.

[0042] Receptacle 320 also includes a receptacle ferrule 400 having a
front end 402 and a rear end 404. Receptacle ferrule 400 includes
guide-pin holes 420 formed in receptacle ferrule front end 402 and sized
to receive guide-pin front ends 192.

[0043] Receptacle ferule 400 also includes optical waveguide bores 460
that operably support receptacle optical waveguides 462, such as
receptacle optical fibers. Receptacle ferrule 400 is supported on a
pedestal 470 defined by recess features 338, with receptacle front end
402 residing near electronic device housing side 312. Receptacle ferrule
400 is fixed in place, i.e., it is not configured to move.

[0045]FIG. 7B is similar to FIG. 7A but shows an example fiber optic
interface assembly 570 constituted by plug 20 being matingly engaged with
receptacle 320. As plug 20 engages receptacle 320, the front end 102 of
plug ferrule 100 contacts the front end 402 of receptacle ferrule 400.
However, since receptacle ferrule 400 is fixed in place (i.e., is not
movable), it urges plug ferrule 100 axially towards the rear end 24 of
plug housing 21 as the plug 20 is inserted into receptacle 320. Also, as
plug 20 engages receptacle 320, prongs 38 of plug housing 21 are received
by the complementary receptacle recess features 338, which serve to align
plug 20 and receptacle 320, e.g., maintain their respective axes A1 and
A2 as substantially coaxial. In addition, guide pins front ends 192 of
plug ferrule 100 enter guide-pin holes 420 of receptacle ferrule 400.

[0046] When plug 20 and receptacle 320 are fully engaged, prongs 38 are
fully engaged within receptacle recess features 338, guide pin front ends
192 are fully engaged with guide-pin holes, and the plug and ferrule
front ends 102 and 402 are in contact, with waveguide bores 160 and 460
being substantially aligned with one another. In addition, plug ferrule
100 is in its rear-biased (i.e., retracted position) with resilient
member 150 being in a compressed state. The distance D between the
forward-biased position (as denoted by dashed line 22R representing
recessed end 22R of plug housing 21) and the rear-biased position (as
denoted by the dashed line 102L corresponding to ferrule front end 102)
is shown in FIG. 7B.

[0047] In an example, the friction established by the mating engagement of
plug 20 and receptacle 320 is sufficient to overcome the spring force of
resilient member 150 pushing against plug ferrule 100, which force might
otherwise act to push the plug out of the receptacle in the absence of a
friction holding force.

[0048] FIG. 8A is a front-elevated view similar to FIG. 2, and FIG. 8B is
a partial cut-away view that illustrates an example embodiment of fiber
optic cable assembly 10 having a plug 20 that includes gradient-index
(GRIN) lenses 600. GRIN lenses 600 each have a front surface 602 and a
rear surface 604. GRIN lenses 600 are arranged in waveguide bores 160
with GRIN lens front surfaces 602 at respective bore front ends 162 or
slightly recessed therefrom (e.g., by up to about 100 microns). Optical
fibers 52 are arranged in respective waveguide bores 160 such that each
optical fiber end 52E is adjacent (e.g., is in contact with) the
corresponding rear surface 604 of a GRIN lens 600.

[0049] FIG. 9 is similar to FIG. 7B and illustrates an example embodiment
of fiber optic interface assembly 570 where plug 20 and receptacle 320
include respective GRIN lenses 600 and 600'. FIG. 10 is a close-up view
of the interface of plug 20 and receptacle 320 showing the interfaced
GRIN lenses 600 and 600'. Each GRIN lens 600' has a front surface 602'
and a rear surface 604'. GRIN lenses 600' are supported by receptacle
ferrule 400 in receptacle ferrule waveguide bores 460 so that GRIN lens
front surfaces 602' coincide with receptacle ferrule front end 402, or
are slightly set back therefrom (e.g., by up to about 100 microns).
Receptacle optical waveguides 462 are arranged in receptacle ferrule
waveguide bores 460 such that the receptacle optical waveguide ends 462E
are arranged adjacent (e.g., in contact with) GRIN lens rear surfaces
604'.

[0050] In an example, two GRIN lenses 600 are included in plug 20 as
transmit and receive GRIN lenses associated with transmit and receive
plug optical fibers 52, and two GRIN lenses 600' are included in
receptacle 320 as transmit and receive GRIN lenses associated with
transmit and receive receptacle optical fibers 462.

[0053] It will be apparent to those skilled in the art that various
modifications and variations can be made to the present disclosure
without departing from the spirit and scope of the disclosure. Thus, it
is intended that the present disclosure cover the modifications and
variations of this disclosure provided they come within the scope of the
appended claims and their equivalents.